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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, base class
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 *
8 * class skeleton from drivers/hwmon/hwmon.c
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/rtc.h>
16#include <linux/kdev_t.h>
17#include <linux/idr.h>
18#include <linux/slab.h>
19#include <linux/workqueue.h>
20
21#include "rtc-core.h"
22
23static DEFINE_IDA(rtc_ida);
24
25static void rtc_device_release(struct device *dev)
26{
27 struct rtc_device *rtc = to_rtc_device(dev);
28 struct timerqueue_head *head = &rtc->timerqueue;
29 struct timerqueue_node *node;
30
31 mutex_lock(&rtc->ops_lock);
32 while ((node = timerqueue_getnext(head)))
33 timerqueue_del(head, node);
34 mutex_unlock(&rtc->ops_lock);
35
36 cancel_work_sync(&rtc->irqwork);
37
38 ida_free(&rtc_ida, rtc->id);
39 mutex_destroy(&rtc->ops_lock);
40 kfree(rtc);
41}
42
43#ifdef CONFIG_RTC_HCTOSYS_DEVICE
44/* Result of the last RTC to system clock attempt. */
45int rtc_hctosys_ret = -ENODEV;
46
47/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
48 * whether it stores the most close value or the value with partial
49 * seconds truncated. However, it is important that we use it to store
50 * the truncated value. This is because otherwise it is necessary,
51 * in an rtc sync function, to read both xtime.tv_sec and
52 * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
53 * of >32bits is not possible. So storing the most close value would
54 * slow down the sync API. So here we have the truncated value and
55 * the best guess is to add 0.5s.
56 */
57
58static void rtc_hctosys(struct rtc_device *rtc)
59{
60 int err;
61 struct rtc_time tm;
62 struct timespec64 tv64 = {
63 .tv_nsec = NSEC_PER_SEC >> 1,
64 };
65
66 err = rtc_read_time(rtc, &tm);
67 if (err) {
68 dev_err(rtc->dev.parent,
69 "hctosys: unable to read the hardware clock\n");
70 goto err_read;
71 }
72
73 tv64.tv_sec = rtc_tm_to_time64(&tm);
74
75#if BITS_PER_LONG == 32
76 if (tv64.tv_sec > INT_MAX) {
77 err = -ERANGE;
78 goto err_read;
79 }
80#endif
81
82 err = do_settimeofday64(&tv64);
83
84 dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
85 &tm, (long long)tv64.tv_sec);
86
87err_read:
88 rtc_hctosys_ret = err;
89}
90#endif
91
92#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
93/*
94 * On suspend(), measure the delta between one RTC and the
95 * system's wall clock; restore it on resume().
96 */
97
98static struct timespec64 old_rtc, old_system, old_delta;
99
100static int rtc_suspend(struct device *dev)
101{
102 struct rtc_device *rtc = to_rtc_device(dev);
103 struct rtc_time tm;
104 struct timespec64 delta, delta_delta;
105 int err;
106
107 if (timekeeping_rtc_skipsuspend())
108 return 0;
109
110 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
111 return 0;
112
113 /* snapshot the current RTC and system time at suspend*/
114 err = rtc_read_time(rtc, &tm);
115 if (err < 0) {
116 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
117 return 0;
118 }
119
120 ktime_get_real_ts64(&old_system);
121 old_rtc.tv_sec = rtc_tm_to_time64(&tm);
122
123 /*
124 * To avoid drift caused by repeated suspend/resumes,
125 * which each can add ~1 second drift error,
126 * try to compensate so the difference in system time
127 * and rtc time stays close to constant.
128 */
129 delta = timespec64_sub(old_system, old_rtc);
130 delta_delta = timespec64_sub(delta, old_delta);
131 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
132 /*
133 * if delta_delta is too large, assume time correction
134 * has occurred and set old_delta to the current delta.
135 */
136 old_delta = delta;
137 } else {
138 /* Otherwise try to adjust old_system to compensate */
139 old_system = timespec64_sub(old_system, delta_delta);
140 }
141
142 return 0;
143}
144
145static int rtc_resume(struct device *dev)
146{
147 struct rtc_device *rtc = to_rtc_device(dev);
148 struct rtc_time tm;
149 struct timespec64 new_system, new_rtc;
150 struct timespec64 sleep_time;
151 int err;
152
153 if (timekeeping_rtc_skipresume())
154 return 0;
155
156 rtc_hctosys_ret = -ENODEV;
157 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
158 return 0;
159
160 /* snapshot the current rtc and system time at resume */
161 ktime_get_real_ts64(&new_system);
162 err = rtc_read_time(rtc, &tm);
163 if (err < 0) {
164 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
165 return 0;
166 }
167
168 new_rtc.tv_sec = rtc_tm_to_time64(&tm);
169 new_rtc.tv_nsec = 0;
170
171 if (new_rtc.tv_sec < old_rtc.tv_sec) {
172 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
173 return 0;
174 }
175
176 /* calculate the RTC time delta (sleep time)*/
177 sleep_time = timespec64_sub(new_rtc, old_rtc);
178
179 /*
180 * Since these RTC suspend/resume handlers are not called
181 * at the very end of suspend or the start of resume,
182 * some run-time may pass on either sides of the sleep time
183 * so subtract kernel run-time between rtc_suspend to rtc_resume
184 * to keep things accurate.
185 */
186 sleep_time = timespec64_sub(sleep_time,
187 timespec64_sub(new_system, old_system));
188
189 if (sleep_time.tv_sec >= 0)
190 timekeeping_inject_sleeptime64(&sleep_time);
191 rtc_hctosys_ret = 0;
192 return 0;
193}
194
195static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
196#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
197#else
198#define RTC_CLASS_DEV_PM_OPS NULL
199#endif
200
201const struct class rtc_class = {
202 .name = "rtc",
203 .pm = RTC_CLASS_DEV_PM_OPS,
204};
205
206/* Ensure the caller will set the id before releasing the device */
207static struct rtc_device *rtc_allocate_device(void)
208{
209 struct rtc_device *rtc;
210
211 rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
212 if (!rtc)
213 return NULL;
214
215 device_initialize(&rtc->dev);
216
217 /*
218 * Drivers can revise this default after allocating the device.
219 * The default is what most RTCs do: Increment seconds exactly one
220 * second after the write happened. This adds a default transport
221 * time of 5ms which is at least halfways close to reality.
222 */
223 rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
224
225 rtc->irq_freq = 1;
226 rtc->max_user_freq = 64;
227 rtc->dev.class = &rtc_class;
228 rtc->dev.groups = rtc_get_dev_attribute_groups();
229 rtc->dev.release = rtc_device_release;
230
231 mutex_init(&rtc->ops_lock);
232 spin_lock_init(&rtc->irq_lock);
233 init_waitqueue_head(&rtc->irq_queue);
234
235 /* Init timerqueue */
236 timerqueue_init_head(&rtc->timerqueue);
237 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
238 /* Init aie timer */
239 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc);
240 /* Init uie timer */
241 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
242 /* Init pie timer */
243 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
244 rtc->pie_timer.function = rtc_pie_update_irq;
245 rtc->pie_enabled = 0;
246
247 set_bit(RTC_FEATURE_ALARM, rtc->features);
248 set_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
249
250 return rtc;
251}
252
253static int rtc_device_get_id(struct device *dev)
254{
255 int of_id = -1, id = -1;
256
257 if (dev->of_node)
258 of_id = of_alias_get_id(dev->of_node, "rtc");
259 else if (dev->parent && dev->parent->of_node)
260 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
261
262 if (of_id >= 0) {
263 id = ida_alloc_range(&rtc_ida, of_id, of_id, GFP_KERNEL);
264 if (id < 0)
265 dev_warn(dev, "/aliases ID %d not available\n", of_id);
266 }
267
268 if (id < 0)
269 id = ida_alloc(&rtc_ida, GFP_KERNEL);
270
271 return id;
272}
273
274static void rtc_device_get_offset(struct rtc_device *rtc)
275{
276 time64_t range_secs;
277 u32 start_year;
278 int ret;
279
280 /*
281 * If RTC driver did not implement the range of RTC hardware device,
282 * then we can not expand the RTC range by adding or subtracting one
283 * offset.
284 */
285 if (rtc->range_min == rtc->range_max)
286 return;
287
288 ret = device_property_read_u32(rtc->dev.parent, "start-year",
289 &start_year);
290 if (!ret) {
291 rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
292 rtc->set_start_time = true;
293 }
294
295 /*
296 * If user did not implement the start time for RTC driver, then no
297 * need to expand the RTC range.
298 */
299 if (!rtc->set_start_time)
300 return;
301
302 range_secs = rtc->range_max - rtc->range_min + 1;
303
304 /*
305 * If the start_secs is larger than the maximum seconds (rtc->range_max)
306 * supported by RTC hardware or the maximum seconds of new expanded
307 * range (start_secs + rtc->range_max - rtc->range_min) is less than
308 * rtc->range_min, which means the minimum seconds (rtc->range_min) of
309 * RTC hardware will be mapped to start_secs by adding one offset, so
310 * the offset seconds calculation formula should be:
311 * rtc->offset_secs = rtc->start_secs - rtc->range_min;
312 *
313 * If the start_secs is larger than the minimum seconds (rtc->range_min)
314 * supported by RTC hardware, then there is one region is overlapped
315 * between the original RTC hardware range and the new expanded range,
316 * and this overlapped region do not need to be mapped into the new
317 * expanded range due to it is valid for RTC device. So the minimum
318 * seconds of RTC hardware (rtc->range_min) should be mapped to
319 * rtc->range_max + 1, then the offset seconds formula should be:
320 * rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
321 *
322 * If the start_secs is less than the minimum seconds (rtc->range_min),
323 * which is similar to case 2. So the start_secs should be mapped to
324 * start_secs + rtc->range_max - rtc->range_min + 1, then the
325 * offset seconds formula should be:
326 * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
327 *
328 * Otherwise the offset seconds should be 0.
329 */
330 if (rtc->start_secs > rtc->range_max ||
331 rtc->start_secs + range_secs - 1 < rtc->range_min)
332 rtc->offset_secs = rtc->start_secs - rtc->range_min;
333 else if (rtc->start_secs > rtc->range_min)
334 rtc->offset_secs = range_secs;
335 else if (rtc->start_secs < rtc->range_min)
336 rtc->offset_secs = -range_secs;
337 else
338 rtc->offset_secs = 0;
339}
340
341static void devm_rtc_unregister_device(void *data)
342{
343 struct rtc_device *rtc = data;
344
345 mutex_lock(&rtc->ops_lock);
346 /*
347 * Remove innards of this RTC, then disable it, before
348 * letting any rtc_class_open() users access it again
349 */
350 rtc_proc_del_device(rtc);
351 if (!test_bit(RTC_NO_CDEV, &rtc->flags))
352 cdev_device_del(&rtc->char_dev, &rtc->dev);
353 rtc->ops = NULL;
354 mutex_unlock(&rtc->ops_lock);
355}
356
357static void devm_rtc_release_device(void *res)
358{
359 struct rtc_device *rtc = res;
360
361 put_device(&rtc->dev);
362}
363
364struct rtc_device *devm_rtc_allocate_device(struct device *dev)
365{
366 struct rtc_device *rtc;
367 int id, err;
368
369 id = rtc_device_get_id(dev);
370 if (id < 0)
371 return ERR_PTR(id);
372
373 rtc = rtc_allocate_device();
374 if (!rtc) {
375 ida_free(&rtc_ida, id);
376 return ERR_PTR(-ENOMEM);
377 }
378
379 rtc->id = id;
380 rtc->dev.parent = dev;
381 err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
382 if (err)
383 return ERR_PTR(err);
384
385 err = dev_set_name(&rtc->dev, "rtc%d", id);
386 if (err)
387 return ERR_PTR(err);
388
389 return rtc;
390}
391EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
392
393int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
394{
395 struct rtc_wkalrm alrm;
396 int err;
397
398 if (!rtc->ops) {
399 dev_dbg(&rtc->dev, "no ops set\n");
400 return -EINVAL;
401 }
402
403 if (!rtc->ops->set_alarm)
404 clear_bit(RTC_FEATURE_ALARM, rtc->features);
405
406 if (rtc->ops->set_offset)
407 set_bit(RTC_FEATURE_CORRECTION, rtc->features);
408
409 rtc->owner = owner;
410 rtc_device_get_offset(rtc);
411
412 /* Check to see if there is an ALARM already set in hw */
413 err = __rtc_read_alarm(rtc, &alrm);
414 if (!err && !rtc_valid_tm(&alrm.time))
415 rtc_initialize_alarm(rtc, &alrm);
416
417 rtc_dev_prepare(rtc);
418
419 err = cdev_device_add(&rtc->char_dev, &rtc->dev);
420 if (err) {
421 set_bit(RTC_NO_CDEV, &rtc->flags);
422 dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
423 MAJOR(rtc->dev.devt), rtc->id);
424 } else {
425 dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
426 MAJOR(rtc->dev.devt), rtc->id);
427 }
428
429 rtc_proc_add_device(rtc);
430
431 dev_info(rtc->dev.parent, "registered as %s\n",
432 dev_name(&rtc->dev));
433
434#ifdef CONFIG_RTC_HCTOSYS_DEVICE
435 if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
436 rtc_hctosys(rtc);
437#endif
438
439 return devm_add_action_or_reset(rtc->dev.parent,
440 devm_rtc_unregister_device, rtc);
441}
442EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
443
444/**
445 * devm_rtc_device_register - resource managed rtc_device_register()
446 * @dev: the device to register
447 * @name: the name of the device (unused)
448 * @ops: the rtc operations structure
449 * @owner: the module owner
450 *
451 * @return a struct rtc on success, or an ERR_PTR on error
452 *
453 * Managed rtc_device_register(). The rtc_device returned from this function
454 * are automatically freed on driver detach.
455 * This function is deprecated, use devm_rtc_allocate_device and
456 * rtc_register_device instead
457 */
458struct rtc_device *devm_rtc_device_register(struct device *dev,
459 const char *name,
460 const struct rtc_class_ops *ops,
461 struct module *owner)
462{
463 struct rtc_device *rtc;
464 int err;
465
466 rtc = devm_rtc_allocate_device(dev);
467 if (IS_ERR(rtc))
468 return rtc;
469
470 rtc->ops = ops;
471
472 err = __devm_rtc_register_device(owner, rtc);
473 if (err)
474 return ERR_PTR(err);
475
476 return rtc;
477}
478EXPORT_SYMBOL_GPL(devm_rtc_device_register);
479
480static int __init rtc_init(void)
481{
482 int err;
483
484 err = class_register(&rtc_class);
485 if (err)
486 return err;
487
488 rtc_dev_init();
489
490 return 0;
491}
492subsys_initcall(rtc_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, base class
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 *
8 * class skeleton from drivers/hwmon/hwmon.c
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/rtc.h>
16#include <linux/kdev_t.h>
17#include <linux/idr.h>
18#include <linux/slab.h>
19#include <linux/workqueue.h>
20
21#include "rtc-core.h"
22
23static DEFINE_IDA(rtc_ida);
24struct class *rtc_class;
25
26static void rtc_device_release(struct device *dev)
27{
28 struct rtc_device *rtc = to_rtc_device(dev);
29
30 ida_simple_remove(&rtc_ida, rtc->id);
31 kfree(rtc);
32}
33
34#ifdef CONFIG_RTC_HCTOSYS_DEVICE
35/* Result of the last RTC to system clock attempt. */
36int rtc_hctosys_ret = -ENODEV;
37#endif
38
39#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
40/*
41 * On suspend(), measure the delta between one RTC and the
42 * system's wall clock; restore it on resume().
43 */
44
45static struct timespec64 old_rtc, old_system, old_delta;
46
47static int rtc_suspend(struct device *dev)
48{
49 struct rtc_device *rtc = to_rtc_device(dev);
50 struct rtc_time tm;
51 struct timespec64 delta, delta_delta;
52 int err;
53
54 if (timekeeping_rtc_skipsuspend())
55 return 0;
56
57 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
58 return 0;
59
60 /* snapshot the current RTC and system time at suspend*/
61 err = rtc_read_time(rtc, &tm);
62 if (err < 0) {
63 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
64 return 0;
65 }
66
67 ktime_get_real_ts64(&old_system);
68 old_rtc.tv_sec = rtc_tm_to_time64(&tm);
69
70 /*
71 * To avoid drift caused by repeated suspend/resumes,
72 * which each can add ~1 second drift error,
73 * try to compensate so the difference in system time
74 * and rtc time stays close to constant.
75 */
76 delta = timespec64_sub(old_system, old_rtc);
77 delta_delta = timespec64_sub(delta, old_delta);
78 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
79 /*
80 * if delta_delta is too large, assume time correction
81 * has occurred and set old_delta to the current delta.
82 */
83 old_delta = delta;
84 } else {
85 /* Otherwise try to adjust old_system to compensate */
86 old_system = timespec64_sub(old_system, delta_delta);
87 }
88
89 return 0;
90}
91
92static int rtc_resume(struct device *dev)
93{
94 struct rtc_device *rtc = to_rtc_device(dev);
95 struct rtc_time tm;
96 struct timespec64 new_system, new_rtc;
97 struct timespec64 sleep_time;
98 int err;
99
100 if (timekeeping_rtc_skipresume())
101 return 0;
102
103 rtc_hctosys_ret = -ENODEV;
104 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
105 return 0;
106
107 /* snapshot the current rtc and system time at resume */
108 ktime_get_real_ts64(&new_system);
109 err = rtc_read_time(rtc, &tm);
110 if (err < 0) {
111 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
112 return 0;
113 }
114
115 new_rtc.tv_sec = rtc_tm_to_time64(&tm);
116 new_rtc.tv_nsec = 0;
117
118 if (new_rtc.tv_sec < old_rtc.tv_sec) {
119 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
120 return 0;
121 }
122
123 /* calculate the RTC time delta (sleep time)*/
124 sleep_time = timespec64_sub(new_rtc, old_rtc);
125
126 /*
127 * Since these RTC suspend/resume handlers are not called
128 * at the very end of suspend or the start of resume,
129 * some run-time may pass on either sides of the sleep time
130 * so subtract kernel run-time between rtc_suspend to rtc_resume
131 * to keep things accurate.
132 */
133 sleep_time = timespec64_sub(sleep_time,
134 timespec64_sub(new_system, old_system));
135
136 if (sleep_time.tv_sec >= 0)
137 timekeeping_inject_sleeptime64(&sleep_time);
138 rtc_hctosys_ret = 0;
139 return 0;
140}
141
142static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
143#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
144#else
145#define RTC_CLASS_DEV_PM_OPS NULL
146#endif
147
148/* Ensure the caller will set the id before releasing the device */
149static struct rtc_device *rtc_allocate_device(void)
150{
151 struct rtc_device *rtc;
152
153 rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
154 if (!rtc)
155 return NULL;
156
157 device_initialize(&rtc->dev);
158
159 /* Drivers can revise this default after allocating the device. */
160 rtc->set_offset_nsec = NSEC_PER_SEC / 2;
161
162 rtc->irq_freq = 1;
163 rtc->max_user_freq = 64;
164 rtc->dev.class = rtc_class;
165 rtc->dev.groups = rtc_get_dev_attribute_groups();
166 rtc->dev.release = rtc_device_release;
167
168 mutex_init(&rtc->ops_lock);
169 spin_lock_init(&rtc->irq_lock);
170 init_waitqueue_head(&rtc->irq_queue);
171
172 /* Init timerqueue */
173 timerqueue_init_head(&rtc->timerqueue);
174 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
175 /* Init aie timer */
176 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc);
177 /* Init uie timer */
178 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
179 /* Init pie timer */
180 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
181 rtc->pie_timer.function = rtc_pie_update_irq;
182 rtc->pie_enabled = 0;
183
184 return rtc;
185}
186
187static int rtc_device_get_id(struct device *dev)
188{
189 int of_id = -1, id = -1;
190
191 if (dev->of_node)
192 of_id = of_alias_get_id(dev->of_node, "rtc");
193 else if (dev->parent && dev->parent->of_node)
194 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
195
196 if (of_id >= 0) {
197 id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
198 if (id < 0)
199 dev_warn(dev, "/aliases ID %d not available\n", of_id);
200 }
201
202 if (id < 0)
203 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
204
205 return id;
206}
207
208static void rtc_device_get_offset(struct rtc_device *rtc)
209{
210 time64_t range_secs;
211 u32 start_year;
212 int ret;
213
214 /*
215 * If RTC driver did not implement the range of RTC hardware device,
216 * then we can not expand the RTC range by adding or subtracting one
217 * offset.
218 */
219 if (rtc->range_min == rtc->range_max)
220 return;
221
222 ret = device_property_read_u32(rtc->dev.parent, "start-year",
223 &start_year);
224 if (!ret) {
225 rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
226 rtc->set_start_time = true;
227 }
228
229 /*
230 * If user did not implement the start time for RTC driver, then no
231 * need to expand the RTC range.
232 */
233 if (!rtc->set_start_time)
234 return;
235
236 range_secs = rtc->range_max - rtc->range_min + 1;
237
238 /*
239 * If the start_secs is larger than the maximum seconds (rtc->range_max)
240 * supported by RTC hardware or the maximum seconds of new expanded
241 * range (start_secs + rtc->range_max - rtc->range_min) is less than
242 * rtc->range_min, which means the minimum seconds (rtc->range_min) of
243 * RTC hardware will be mapped to start_secs by adding one offset, so
244 * the offset seconds calculation formula should be:
245 * rtc->offset_secs = rtc->start_secs - rtc->range_min;
246 *
247 * If the start_secs is larger than the minimum seconds (rtc->range_min)
248 * supported by RTC hardware, then there is one region is overlapped
249 * between the original RTC hardware range and the new expanded range,
250 * and this overlapped region do not need to be mapped into the new
251 * expanded range due to it is valid for RTC device. So the minimum
252 * seconds of RTC hardware (rtc->range_min) should be mapped to
253 * rtc->range_max + 1, then the offset seconds formula should be:
254 * rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
255 *
256 * If the start_secs is less than the minimum seconds (rtc->range_min),
257 * which is similar to case 2. So the start_secs should be mapped to
258 * start_secs + rtc->range_max - rtc->range_min + 1, then the
259 * offset seconds formula should be:
260 * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
261 *
262 * Otherwise the offset seconds should be 0.
263 */
264 if (rtc->start_secs > rtc->range_max ||
265 rtc->start_secs + range_secs - 1 < rtc->range_min)
266 rtc->offset_secs = rtc->start_secs - rtc->range_min;
267 else if (rtc->start_secs > rtc->range_min)
268 rtc->offset_secs = range_secs;
269 else if (rtc->start_secs < rtc->range_min)
270 rtc->offset_secs = -range_secs;
271 else
272 rtc->offset_secs = 0;
273}
274
275/**
276 * rtc_device_unregister - removes the previously registered RTC class device
277 *
278 * @rtc: the RTC class device to destroy
279 */
280static void rtc_device_unregister(struct rtc_device *rtc)
281{
282 mutex_lock(&rtc->ops_lock);
283 /*
284 * Remove innards of this RTC, then disable it, before
285 * letting any rtc_class_open() users access it again
286 */
287 rtc_proc_del_device(rtc);
288 cdev_device_del(&rtc->char_dev, &rtc->dev);
289 rtc->ops = NULL;
290 mutex_unlock(&rtc->ops_lock);
291 put_device(&rtc->dev);
292}
293
294static void devm_rtc_release_device(struct device *dev, void *res)
295{
296 struct rtc_device *rtc = *(struct rtc_device **)res;
297
298 rtc_nvmem_unregister(rtc);
299
300 if (rtc->registered)
301 rtc_device_unregister(rtc);
302 else
303 put_device(&rtc->dev);
304}
305
306struct rtc_device *devm_rtc_allocate_device(struct device *dev)
307{
308 struct rtc_device **ptr, *rtc;
309 int id, err;
310
311 id = rtc_device_get_id(dev);
312 if (id < 0)
313 return ERR_PTR(id);
314
315 ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
316 if (!ptr) {
317 err = -ENOMEM;
318 goto exit_ida;
319 }
320
321 rtc = rtc_allocate_device();
322 if (!rtc) {
323 err = -ENOMEM;
324 goto exit_devres;
325 }
326
327 *ptr = rtc;
328 devres_add(dev, ptr);
329
330 rtc->id = id;
331 rtc->dev.parent = dev;
332 dev_set_name(&rtc->dev, "rtc%d", id);
333
334 return rtc;
335
336exit_devres:
337 devres_free(ptr);
338exit_ida:
339 ida_simple_remove(&rtc_ida, id);
340 return ERR_PTR(err);
341}
342EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
343
344int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
345{
346 struct rtc_wkalrm alrm;
347 int err;
348
349 if (!rtc->ops) {
350 dev_dbg(&rtc->dev, "no ops set\n");
351 return -EINVAL;
352 }
353
354 rtc->owner = owner;
355 rtc_device_get_offset(rtc);
356
357 /* Check to see if there is an ALARM already set in hw */
358 err = __rtc_read_alarm(rtc, &alrm);
359 if (!err && !rtc_valid_tm(&alrm.time))
360 rtc_initialize_alarm(rtc, &alrm);
361
362 rtc_dev_prepare(rtc);
363
364 err = cdev_device_add(&rtc->char_dev, &rtc->dev);
365 if (err)
366 dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
367 MAJOR(rtc->dev.devt), rtc->id);
368 else
369 dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
370 MAJOR(rtc->dev.devt), rtc->id);
371
372 rtc_proc_add_device(rtc);
373
374 rtc->registered = true;
375 dev_info(rtc->dev.parent, "registered as %s\n",
376 dev_name(&rtc->dev));
377
378 return 0;
379}
380EXPORT_SYMBOL_GPL(__rtc_register_device);
381
382/**
383 * devm_rtc_device_register - resource managed rtc_device_register()
384 * @dev: the device to register
385 * @name: the name of the device (unused)
386 * @ops: the rtc operations structure
387 * @owner: the module owner
388 *
389 * @return a struct rtc on success, or an ERR_PTR on error
390 *
391 * Managed rtc_device_register(). The rtc_device returned from this function
392 * are automatically freed on driver detach.
393 * This function is deprecated, use devm_rtc_allocate_device and
394 * rtc_register_device instead
395 */
396struct rtc_device *devm_rtc_device_register(struct device *dev,
397 const char *name,
398 const struct rtc_class_ops *ops,
399 struct module *owner)
400{
401 struct rtc_device *rtc;
402 int err;
403
404 rtc = devm_rtc_allocate_device(dev);
405 if (IS_ERR(rtc))
406 return rtc;
407
408 rtc->ops = ops;
409
410 err = __rtc_register_device(owner, rtc);
411 if (err)
412 return ERR_PTR(err);
413
414 return rtc;
415}
416EXPORT_SYMBOL_GPL(devm_rtc_device_register);
417
418static int __init rtc_init(void)
419{
420 rtc_class = class_create(THIS_MODULE, "rtc");
421 if (IS_ERR(rtc_class)) {
422 pr_err("couldn't create class\n");
423 return PTR_ERR(rtc_class);
424 }
425 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
426 rtc_dev_init();
427 return 0;
428}
429subsys_initcall(rtc_init);